Sensitometers are well known in the photographic art as an apparatus for generating sensitometric test strips from light-sensitive material (such as photographic paper, film, and the like) to determine the resolution response from the material. A sensitometer generally comprises a light source and means for producing a graded series of exposures (also referred to as line exposures) of the light-sensitive material being tested, such as an optical wedge having a series of steps of known absorbing power.
Some known methods of producing a graded series of exposures (also referred to as line exposures) of the light-sensitive material involve the displacement of a light beam (or laser beam) following reflection on a rotating prism or rotating polygon. A rapid scanning of the light beam caused by the rotating prism or polygon also produces an exposure time. Other known methods vary and control the laser intensity on an exposure using an acousto-optical modulator (AOM).
U.S. Pat. No. 3,677,653 (Hocker) teaches a sensitometer employed to make a sensitometric test strip. U.S. Pat. No. 5,053,519 (Arimoto) relates to an optical system using rotating polygons. U.S. Pat. No. 6,236,461 (Duarte), commonly assigned and incorporated herewith by reference, discloses a laser sensitometer that does not employ an AOM or a rotating prism or polygon. U.S. Pat. No. 5,255,069 (Duarte), commonly assigned and incorporated herewith by reference, discloses an interferometric system for examining and characterizing ultra fine details of various specimens, such as a piece of photographic film.
While such systems may have achieved certain degrees of success in their particular applications, there continues to be a need for a simple, reliable laser sensitometer.